Added functions for finding the min and max elements of a sparse vector.

dlib/svm/sparse_vector.h

@@ -564,6 +564,42 @@ namespace dlib
                 dest(i->first) -= C*i->second;
         }
 
+    // ------------------------------------------------------------------------------------
+
+        template <typename T>
+        typename T::value_type::second_type min (
+            const T& a
+        )
+        {
+            typedef typename T::value_type::second_type type;
+
+            type temp = 0;
+            for (typename T::const_iterator i = a.begin(); i != a.end(); ++i)
+            {
+                if (temp > i->second)
+                    temp = i->second;
+            }
+            return temp;
+        }
+
+    // ------------------------------------------------------------------------------------
+
+        template <typename T>
+        typename T::value_type::second_type max (
+            const T& a
+        )
+        {
+            typedef typename T::value_type::second_type type;
+
+            type temp = 0;
+            for (typename T::const_iterator i = a.begin(); i != a.end(); ++i)
+            {
+                if (temp < i->second)
+                    temp = i->second;
+            }
+            return temp;
+        }
+
     // ------------------------------------------------------------------------------------
 
     }

dlib/svm/sparse_vector_abstract.h

@@ -308,6 +308,34 @@ namespace dlib
 
     // ----------------------------------------------------------------------------------------
 
+        template <typename T>
+        typename T::value_type::second_type min (
+            const T& vect
+        );
+        /*!
+            requires
+                - T == an unsorted sparse vector
+            ensures
+                - returns the minimum value in the sparse vector vect.  Note that
+                  this value is always <= 0 since a sparse vector has an unlimited number
+                  of 0 elements.
+        !*/
+
+    // ------------------------------------------------------------------------------------
+
+        template <typename T>
+        typename T::value_type::second_type max (
+            const T& vect
+        );
+        /*!
+            requires
+                - T == an unsorted sparse vector
+            ensures
+                - returns the maximum value in the sparse vector vect.  Note that
+                  this value is always >= 0 since a sparse vector has an unlimited number
+                  of 0 elements.
+        !*/
+
     }
 
 // ----------------------------------------------------------------------------------------